21121555953 has 8 divisors (see below), whose sum is σ = 28192991616. Its totient is φ = 14065578800.

The previous prime is 21121555909. The next prime is 21121555957. The reversal of 21121555953 is 35955512112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21121555953 - 2¹³ = 21121547761 is a prime.

It is a super-2 number, since 2×21121555953² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21121555957) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3861438 + ... + 3866903.

It is an arithmetic number, because the mean of its divisors is an integer number (3524123952).

Almost surely, 2^21121555953 is an apocalyptic number.

It is an amenable number.

21121555953 is a deficient number, since it is larger than the sum of its proper divisors (7071435663).

21121555953 is an equidigital number, since it uses as much as digits as its factorization.

21121555953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7729255.

The product of its digits is 67500, while the sum is 39.

The spelling of 21121555953 in words is "twenty-one billion, one hundred twenty-one million, five hundred fifty-five thousand, nine hundred fifty-three".